The objectives in this paper were to analyse noise effects on episodic and semantic memory performance in different age groups, and to see whether age interacted with noise in their effects on memory. Data were taken from three separate previous experiments, that were performed with the same design, procedure and dependent measures with participants from four age groups (13-14, 18-20, 35-45 and 55-65 years). Participants were randomly assigned to one of three conditions: (a) meaningful irrelevant speech, (b) road traffic noise, and (c) quiet. The results showed effects of both noise sources on a majority of the dependent measures, both when taken alone and aggregated according to the nature of the material to be memorised. However, the noise effects for episodic memory tasks were stronger than for semantic memory tasks. Further, in the reading comprehension task, cued recall and recognition were more impaired by meaningful irrelevant speech than by road traffic noise. Contrary to predictions, there was no interaction between noise and age group, indicating that the obtained noise effects were not related to the capacity to perform the task. The results from the three experiments taken together throw more light on the relative effects of road traffic noise and meaningful irrelevant speech on memory performance in different age groups.

Psychological effects of aircraft noise exposure on children have only recently been addressed in the References. The current study took advantage of a natural experiment caused by the opening of a major new airport, exposing children in a formerly quiet area to aircraft noise. In this prospective longitudinal investigation, which employed nan-exposed control groups, effects of aircraft noise prior to and subsequent to inauguration of the new airport as well as effects of chronic noise and its reduction at the old airport (6 and 18 month post relocation), were studied in 326 children aged 9 to 13 years. The psychological health of children was investigated with a standardized quality of life scale as well as with a motivational measure derived from the Glass and Singer stress aftereffects paradigm. In addition a self report noise annoyance scale was used. In the children studied at the two airports over three time points, results showed a significant decrease of total quality of life 18 month after aircraft noise exposure as well as a motivational deficits operationalized by fewer attempts to solve insoluble puzzles in the new airport area. Parallel shifts in children's attributions for failure were also noted. At the old airport parallel impairments were present before the airport relocation but subsided there after. These findings are in accord with reports of impaired psychological health after noise exposure and indicate the relevance of monitoring psychological parameters as a function of environmental stressors among children.

4. Structural equation models of memory performance across noise and age

Enmarker, Ingela

et al.

University of Gävle, Department of Education and Psychology, Ämnesavdelningen för psykologi. Royal Institute of Technology, Stockholm, Sweden.

Boman, Eva

University of Gävle, Department of Education and Psychology, Ämnesavdelningen för psykologi. Royal Institute of Technology, Stockholm, Sweden.

Hygge, Staffan

University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.

Competing models of declarative memory were tested with structural equation models to analyze whether a second-order latent variable structure for episodic and semantic memory was invariant across age groups and across noise exposure conditions. Data were taken from three previous experimental noise studies that were performed with the same design, procedure, and dependent measures, and with participants from four age groups (13-14, 18-20, 35-45, and 55-65 years). Two noise conditions, road traffic noise and meaningful irrelevant speech, were compared to a quiet control group. The structural models put to the test were taken from Nyberg et al. (2003), which employed several memory tests that were the same as ours and studied age-groups that partly overlapped with our groups. In addition we also varied noise exposure conditions. Our analyses replicated and supported the second-order semantic-episodic memory models in Nyberg et al. (2003). The latent variable structures were invariant across age groups, with the exception of our youngest group, which by itself showed a less clear latent structure. The obtained structures were also invariant across noise exposure conditions. We also noted that our text memory items, which did not have a counterpart in the study by Nyberg et al. (2003), tend to form a separate latent variable loading on episodic memory.

Chronic exposure to aircraft noise elevated psychophysiological stress (resting blood pressure and overnight epinephrine and norepinephrine) and depressed quality-of-life indicators over a 2-year period among 9- to 11-year-old children. Data collected before and after the inauguration of a major new international airport in noise-impacted and comparison communities show that noise significantly elevates stress among children at ambient levels far below those necessary to produce hearing damage.

This article illustrates the value of incorporating psychological principles into the environmental sciences. Psycho-physiological, cognitive, motivational, and affective indices of stress were monitored among elementary school children chronically exposed to aircraft noise. We demonstrate for the first time that chronic noise exposure is associated with elevated neuroendocrine and cardiovascular measures, muted cardiovascular reactivity to a task presented under acute noise, deficits in a standardized reading test administered under quiet conditions, poorer long-term memory, and diminished quality of life on a standardized index. Children in high-noise areas also showed evidence of poor persistence on challenging tasks and habituation to auditory distraction on a signal-to-noise task. They reported considerable annoyance with community noise levels, as measured utilizing a calibration procedure that adjusts for individual differences in rating criteria for annoyance judgments.

Background. Previous field studies have indicated that children's cognitive performance is impaired by chronic aircraft noise exposure. However, these studies have not been of sufficient size to account adequately for the role of confounding factors. The objective of this study was to test whether cognitive impairments and stress responses (catecholamines, cortisol and perceived stress) are attributable to aircraft noise exposure after adjustment for school and individual level confounding factors and to examine whether children exposed to high levels of social disadvantage are at greater risk of noise effects. Methods. The cognitive performance and health of 451 children aged 8-11 years, attending 10 schools in high aircraft noise areas (16 h outdoor Leq > 63 dBA) was compared with children attending 10 matched control schools exposed to lower levels of aircraft noise (16 h outdoor Leq < 57 dBA). Results. Noise exposure was associated with impaired reading on difficult items and raised annoyance, after adjustment for age, main language spoken and household deprivation. There was no variation in the size of the noise effects in vulnerable subgroups of children. High levels of noise exposure were not associated with impairments in mean reading score, memory and attention or stress responses. Aircraft noise was weakly associated with hyperactivity and psychological morbidity. Conclusions. Chronic noise exposure is associated with raised noise annoyance in children. The cognitive results indicate that chronic aircraft noise exposure does not always lead to generalized cognitive effects but, rather, more selective cognitive impairments on difficult cognitive tests in children.

12. Acoustical conditions in the classroom

Hurtig, Anders

et al.

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology. Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University and Department of Sports and Medicine, University of Dalarna, Sweden .

Hygge, Staffan

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Kjellberg, Anders

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Nöstl, Anatole

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Keus van de Poll, Marijke

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Ljung, Robert

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Noise impairs speech perception which in turn makes memory and learning more difficult. School children are expected to be particularly vulnerable to the negative effects of noise. In this study we varied reverberation time (RT) and signal-to-noise ratio (SNR) to see how they affected recall of words in Swedish (native tongue) and English. Participants were 72 children in the fourth grade who listened to wordlists presented in Swedish and English with broadband noise in the background. We compared two reverberation time (RT) conditions: a short RT (0.3 sec.) and a long RT (1.2 sec.), and two signal-to-noise (SNR) conditions: a low SNR (+3 dB) and a high SNR (+12 dB). Each wordlist had 8 words to be recalled. Main effects of language and SNR were found. Children could recall fewer words if they were presented in English or had a low SNR. Interactions were found between Language, RT, SNR and whether the words were at the beginning, in the middle or at the end of the wordlists. Recall performance was best with a short RT and a high SNR. Fourth graders recalled more words in their native language compared to English. Children might have difficulties with semantic association and understanding the meaning of words in English. Recall performance was markedly improved with good listening conditions, which indicates that there is something to be gained by improving the acoustical conditions in a classroom to improve memory and learning.

14. Children’s recall of words spoken in their first and second language

Hurtig, Anders

et al.

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology. Linnaeus Centre HEAD, Swedish Institute for Disability Research, University of Linköping, Linköping, Sweden; Department of Education, Health and Social Studies, University of Dalarna, Falun, Sweden.

Keus van de Poll, Marijke

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Pekkola, Elina

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Hygge, Staffan

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Ljung, Robert

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Speech perception runs smoothly and automatically when there is silence in the background, but when the speech signal is degraded by background noise or by reverberation, effortful cognitive processing is needed to compensate for the signal distortion. Previous research has typically investigated the effects of signal-to-noise ratio (SNR) and reverberation time in isolation, whilst few have looked at their interaction. In this study, we probed how reverberation time and SNR influence recall of words presented in participants’ first- (L1) and second-language (L2). A total of 72 children (10 years old) participated in this study. The to-be-recalled wordlists were played back with two different reverberation times (0.3 and 1.2 sec) crossed with two different SNRs (+3 dBA and +12 dBA). Children recalled fewer words when the spoken words were presented in L2 in comparison with recall of spoken words presented in L1. Words that were presented with a high SNR (+12 dBA) improved recall compared to a low SNR (+3 dBA). Reverberation time interacted with SNR to the effect that at +12 dB the shorter reverberation time improved recall, but at +3 dB it impaired recall. The effects of the physical sound variables (SNR and reverberation time) did not interact with language.

The purpose of this experiment was to explore whether listening positions (close or distant location from the sound source) in the classroom, and classroom reverberation, influence students’ score on a test for second-language (L2) listening comprehension (i.e., comprehension of English in Swedish speaking participants). The listening comprehension test administered was part of a standardized national test of English used in the Swedish school system. A total of 125 high school pupils, 15 years old, participated. Listening position was manipulated within subjects, classroom reverberation between subjects. The results showed that L2 listening comprehension decreased as distance from the sound source increased. The effect of reverberation was qualified by the participants’ baseline L2 proficiency. A shorter reverberation was beneficial to participants with high L2 proficiency, while the opposite pattern was found among the participants with low L2 proficiency. The results indicate that listening comprehension scores—and hence students’ grade in English—may depend on students’ classroom listening position.

The acoustical conditions in a classroom may severely impair listening, which in turn impairs learning. To safe-guard against inferior listening conditions government agencies and professional societies have established building codes and recommendations for acceptable signal-to-noise ratios (SNR) and reverberation times (RT) in classrooms. Codes and recommendations are based on conditions required for speech intelligibility and correct identification of spoken words and isolated sentences. Correct identification of what was said is a necessary condition for memory and learning, but it is not a sufficient one. There is a gap between speech intelligibility and memory and the size of that gap is a function of the intelligibility of the spoken message and how much the message taxes the individual's limited working memory capacity. I will discuss how SN, RT and their combinations change speech intelligibility and memory of spoken messages. Although the characteristics of the spoken material and the individual's working memory capacities can be assessed independently of each other, there is a functional equivalence between them. A difficult task and a lack of skill are two sides of the same coin. In a better world building codes and recommendations for classroom acoustics should be based on memory and learning rather than on speech intelligibility alone.

18. Classroom experiments on the effects of different noise sources and sound levels on long-term recall and recognition in children

Hygge, Staffan

University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.

A total of 1358 children aged 12-14 years participated in ten noise experiments in their ordinary classrooms and were tested for recall and recognition of a text exactly one week later. Single and combined noise sources were presented for 15 min at 66 dBA L-eq (equivalent noise level). Single source presentations of aircraft and road traffic noise were also presented at 55 dBA L-eq. Data were analysed between subjects since the first within-subjects analysis revealed a noise after-effect or a asymmetric transfer effect. Overall, there was a strong noise effect on recall, and a smaller, but significant effect on recognition. In the single-source studies, aircraft and road traffic noise impaired recall at both noise levels. Train noise and verbal noise did not affect recognition or recall. Some of the pairwise combinations of aircraft noise with train or road traffic, with one or the other as the dominant source, interfered with recall and recognition. Item difficulty, item position and ability did not interact with the noise effect. Arousal, distraction, perceived effort, and perceived difficulty in reading and learning did not mediate the effects on recall and recognition.

The acoustical conditions in a classroom may severely impair listening, which in turn impairs learning. To safe-guard against inferior listening conditions government agencies and professional societies have established building codes and recommendations for acceptable signal-to-noise ratios (SNR) and reverberation times (RT) in classrooms. Codes and recommendations are based on conditions required for speech intelligibility and correct identification of spoken words and isolated sentences.

Correct identification of what was said is a necessary condition for memory and learning, but it is not a sufficient one. There is a gap between speech intelligibility and memory and the size of that gap is a function of the intelligibility of the spoken message and how much the message taxes the individual's limited working memory capacity.

I will discuss how SN, RT and their combinations change speech intelligibility and memory of spoken messages. Although the characteristics of the spoken material and the individual's working memory capacities can be assessed independently of each other, there is a functional equivalence between them. A difficult task and a lack of skill are two sides of the same coin.

In a better world building codes and recommendations for classroom acoustics should be based on memory and learning rather than on speech intelligibility alone.

The traditional way set up noise dose-effect relationships is to rely on cross-sectional studies, where narrow bands of actual or projected noise exposure levels are plotted against an effect, e.g. self-reported annoyance. When there is an abundance of noise levels to compute from, and a common scale for the effect measures, this procedure is straightforward. Means and confidence intervals of e.g. annoyance at a given noise level can be presented. However, setting up dose-effect relationships can be approached from another point if view. If the focus is shifted away from generating levels of effect at different noises doses to the relative change in effect by lowering or increasing the noise dose, the relevant information is found in the slope or 1st derivative of the noise dose-effect relationship. Just plotting noise-effect slopes from different studies, will, if the grouping of the slopes come out in a coherent and orderly way, set a platform for statements about gains and losses in effects as a result of changes in levels. This was done in the present paper for a set of cognitive outcomes of noise exposure. The results showed that reading and recall memory were the cognitive outcomes with the steepest slopes.

Noise: nature and measurement Noise is often defined as unwanted sound or sounds that have an adverse effect on humans. What is sweet music for one person may be noise to someone else. Thus, noise is a psychological construct influenced both by physical and psychosocial properties. Sound is created by the rapidly changing pressure of air molecules at the eardrum. A single tone, such as that from a tuning fork, can be depicted as a fixed wavelength sinusoidal pressure distribution across time. The number of pressure cycles per second, measured in hertz (Hz), is the basis for the sensation of pitch. A healthy young ear is sensitive to sounds between approximately 20 Hz and up to 20 kHz. The amplitude of the sine wave is perceived as loudness. To accommodate the wide dynamic power range of the human ear a logarithmic magnitude scale for sounds has been introduced. Its unit is the decibel (dB). Adding two independent sound sources of the same dB-level will yield a sum that is ≈3 dB higher than one of them alone. The subjective effect of a change in 3 dB amounts to a just perceptible change. A change of around 10 dB is needed to experience the sound as twice as loud. The hearing threshold for pure tones is lowest in the frequency range 500–4000 Hz, which also is the range where human speech has its maximum energy content.

In four recent experiments we have seen that a long reverberation time (RvT) may improve, rather than impair, comprehension and recall of spoken words or texts for participants who have limited language skills. A long RvT improved, rather than impaired, comprehension for Swedish pupils with a low proficiency in English reading when taking a grade 9 English listening comprehension test in their classroom. For those who were good at reading English there was a better recall with a short RvT. This crossover antagonistic interaction was replicated with Swedish college students grouped by their English proficiency reading skills. In two word list experiments with Swedish pupils in grade 4 and college students, English and Swedish words were presented with a long and short RvT and crossed with two signal-to-noise ratios. Also here there were indicators of a crossover interaction to the effects that along reverberation time improved, rather than impaired, the recall of the words for students that were on the low side of English language proficiency. Possible explanations will be discussed in the presentation.

30. An experiment with children in the first grade to reduce their self-generated noiseHygge, Staffan

To explore why noise has reliable effects on delayed recall in a certain text-reading task, this episodic memory task was employed with other memory tests in a study of road traffic noise and meaningful but irrelevant speech. Context-dependent memory was tested and self-reports of affect were taken. Participants were 96 high school students. The results showed that both road traffic noise and meaningful irrelevant speech impaired recall of the text. Retrieval in noise from semantic memory was also impaired. Attention was impaired by both noise sources, but attention did not mediate the noise effects on episodic memory. Recognition was not affected by noise. Context-dependent memory was Dot shown. The lack of mediation by attention, and road traffic noise being as harmful as meaningful irrelevant speech, are discussed in relation to where in the input/storing/output sequence noise has its effect and what the distinctive feature of the disturbing noise is.

Before the opening of the new Munich International Airport and the termination of the old airport, children near both sites were recruited into aircraft-noise groups (aircraft noise at present or pending) and control groups with no aircraft noise (closely matched for socioeconomic status). A total of 326 children (mean age = 10.4 years) took part in three data-collection waves, one before and two after the switch-over of the airports. After the switch, long-term memory and reading were impaired in the noise group at the new airport. and improved in the formerly noise-exposed group at the old airport. Short-term memory also improved in the latter group after the old airport was closed. At the new airport, speech perception was impaired in the newly noise-exposed group. Mediational analyses suggest that poorer reading was not mediated by speech perception, and that impaired recall was in part mediated by reading.

Some conditions that people would not ordinarily appraise as demanding may constrain restoration when experienced in places sought out for restoration. The constraint of restoration by community noise exemplifies this phenomenon. Community noise regulations assume a moderating effect of context on noise annoyance, in that they impose stricter controls on sound levels in locations and at times normally dedicated to restoration. To further explore the constrained restoration phenomenon, in this paper we review research on reactions to human-produced sounds in natural settings, like parks, which many people particularly value for restoration. We also consider ambient sound qualities that promote restoration

Free recall of spoken words in Swedish (native tongue) and English were assessed in two signal-to-noise ratio (SNR) conditions (+3 and +12 dB), with and without half of the heard words being repeated back orally directly after presentation [shadowing, speech intelligibility (SI)]. A total of 24 word lists with 12 words each were presented in English and in Swedish to Swedish speaking college students. Pre-experimental measures of working memory capacity (operation span, OSPAN) were taken. A basic hypothesis was that the recall of the words would be impaired when the encoding of the words required more processing resources, thereby depleting working memory resources. This would be the case when the SNR was low or when the language was English. A low SNR was also expected to impair SI, but we wanted to compare the sizes of the SNR-effects on SI and recall. A low score on working memory capacity was expected to further add to the negative effects of SNR and language on both SI and recall. The results indicated that SNR had strong effects on both SI and recall, but also that the effect size was larger for recall than for SI. Language had a main effect on recall, but not on SI. The shadowing procedure had different effects on recall of the early and late parts of the word lists. Working memory capacity was unimportant for the effect on SI and recall. Thus, recall appear to be a more sensitive indicator than SI for the acoustics of learning, which has implications for building codes and recommendations concerning classrooms and other workplaces, where both hearing and learning is important.

An experiment will be reported which assessed speech intelligibility and free recall of spoken words in Swedish (native tongue) and in English heard under different signal-to-noise (S/N) ratios (+3 and +12 dB), and with/without the spoken words being repeated back orally directly after presentation (shadowing). All participants encountered all experimental conditions. Twelve wordlists with 12 words each were generated in English as well as in Swedish. The words were chosen according to their ranks in category norms for the two languages, and no category was the same for the two languages. Blocks of counter balanced presentation orders, S/N-ratios and shadowing/no shadowing were generated. After each wordlist the participants wrote down the words they could recall. Pre-experimental measures of working memory capacity were taken. The basic hypotheses for the recall of the words were that working memory would be overloaded when the S/N-ratio was low, there was no shadowing and when the language was English. A low score on working memory capacity was expected to further enhance these effects. While writing this abstract data collection is still in progress but results will be presented at the conference.

This study explored speech intelligibility and free recall of word lists heard under different signal-to-noise (S/N) ratios. Pre-experimental measures of working memory capacity (WMC) were taken to explore individual susceptibility to the disruptive effects of noise. The thirty-five participants first completed a WMC-operation span task in quiet and later listened to spoken word lists containing 11 one-syllable phonetically balanced words presented at four different S/N ratios (+12, +9, +6, and +3). Participants repeated (shadowed) each word aloud immediately after its presentation and performed a free recall task of the words after the end of the list. The speech intelligibility function decreased linearly with increasing S/N levels for both the high-WMC and low-WMC groups. Recall and memory of the words decreased with increasing S/N levels only for the low-WMC group. Recall and memory for the high-WMC individuals was not affected by increased S/N levels. Our results suggest that impoverished acoustical conditions impair speech intelligibility and memory, but also that a high WMC may counteract some of the negative effects of speech noise.

43. POE Post occupancy evaluation of daylight in buildings

Hygge, Staffan

et al.

University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.

Two experiments will be presented which assessed free recall of spoken words in Swedish (native tongue) and in English heard under different signal-to-noise ratios (SNR: +3 and +12 dB), and different reverberation times (RT: 0.3 and 1.2 s). All participants encountered these eight experimental conditions (Language*SNR*RT). The first experiment was run with college student (N=48), who were run individually. In the second experiment children in grade 4 (10-11 years, N=72) took part and they were run as a group in their regular classrooms.

Twelve wordlists in English and twelve wordlists in Swedish were generated. The words were chosen according to their ranks in category norms for the two languages. The number of words in each list was 12 for the college group and 8 for children in Grade 4. The 2 x 12 wordlists were presented in counter balanced presentation orders in three blocks (Blocks). To compare primacy and recency effects the word lists were divided into three parts (p3rd). After each wordlist the participants typed in or wrote down the words they could recall.

The basic hypotheses for the recall of the words were that working memory would be overloaded when the SNR was low and the RT was long, and that SNR and RT would interact with each other, with Language and with Study (Grade4/College). The analyses suggest that for both groups there were expected effects of language and of SNR, but the effect of RT was smaller and only showed up in interactions.

45. Recall of spoken words in English and Swedish heard at different signal-to-noise ratios and different reverberation times

Hygge, Staffan

et al.

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Nöstl, Anatole

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Hurtig, Anders

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Haga, Andreas

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Holmgren, Mattias

University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology.

Two experiments will be presented which assessed free recall of spoken words in Swedish (native tongue) and in English heard under different signal-to-noise (SN) ratios (+3 and +12 dB), and different reverberation time (RT, .3 and 1.2 sec). All participants encountered all eight experimental conditions (Language*SN*RT). The first experiment was run with college student (N=48) and they were run individually. In the second experiment children in grade 4 (10-11 years, N=72) took part and they were run in the regular classrooms.

Twelve wordlists in Swedish and twelve wordlists in English generated. The words were chosen according to their ranks in category norms for the two languages, and no category was the same for the two languages. The number of words in each list was 12 for the college group and 8 for grade four. The 2 x 12 wordlists were presented in counter balanced presentation orders in three blocks. Within each block order of S/N and RT was also counterbalanced. After each wordlist the participants wrote down the words they could recall. Pre-experimental measures of working memory capacity were also taken.

The basic hypotheses for the recall of the words were that working memory would be overloaded when the SN-ratio was low and the RT was long, and that SN and RT would interact with each other, with Language and with Age-group.

To compare primacy and recency effects the word lists were divided into three parts (p3rd). After each wordlist the participants typed in or wrote down the words they could recall.

The basic hypotheses for the recall of the words were that working memory would be overloaded when the SNR was low and the RT was long, and that SNR and RT would interact with each other, with Language and with Study (Grade4/College). The analyses suggest that for both groups there were expected effects of language and of SNR, but the effect of RT was smaller and only showed up in interactions.

The performance on a conversation-following task by 24 hearing-impaired persons was compared with that of 24 matched controls with normal hearing in the presence of three background noises: (a) speech-spectrum random noise, (b) a male voice, and (c) the male voice played in reverse. The subjects' task was to readjust the sound level of a female voice (signal), every time the signal voice was attenuated, to the subjective level at which it was just possible to understand what was being said. To assess the benefit of lipreading, half of the material was presented audiovisually and half auditorily only. It was predicted that background speech would have a greater masking effect than reversed speech, which would in turn have a lesser masking effect than random noise. It was predicted that hearing-impaired subjects would perform more poorly than the normal-hearing controls in a background of speech. The influence of lipreading was expected to be constant across groups and conditions. The results showed that the hearing-impaired subjects were equally affected by the three background noises and that normal-hearing persons were less affected by the background speech than by noise. The performance of the normal-hearing persons was superior to that of the hearing-impaired subjects. The prediction about lipreading was confirmed. The results were explained in terms of the reduced temporal resolution by the hearing-impaired subjects.

The aim of the present study was to investigate cognitive, emotional, and physiological effects of two background noise conditions (high noise: 51 LAeq and low noise: 39 LAeq) during work in a simulated open-plan office, followed by four restoration conditions (river movie with sound, only river sound, silence, and office noise) after the work period. Students (N = 47) went through one practice session and two experimental sessions, one each with the low and high noise conditions. In each experimental session they worked for two hours with tasks involving basic working memory processes. We also took physiological measures of stress (cortisol and catecholamine) and self-reports of mood and fatigue. The results showed that the participants remembered fewer words, rated themselves as more tired and less motivated in high noise compared to low noise. The participants showed high levels of cortisol when they arrived to the experimental session and they had a significant (p <.001) decline in both noise conditions after two hours of work. An identical decline was shown in the norepinephrine levels (p < 0.001). The restoration phase also indicated that the sound conditions may promote different restorative experiences. To conclude, the present study showed that noise level can be of importance for working memory performance and subjective feelings of tiredness and motivation in an open-plan office and that varying sound conditions may promote different restorative experiences.